Welcome to the iRhythm Technologies, Inc. Q1 2023 Earnings Conference Call. My name is Lauren, and I will be coordinating your call today. I will now hand over to Stephanie Zhadkevich, Director of Investor Relations, to begin. Stephanie, please go ahead.

Thank you all for participating in today's call. Earlier today, iRhythm released financial results for the first quarter ended March 31, 2023. Before we begin, I'd like to remind you that management will make statements during this call that include forward-looking statements within the meaning of federal securities laws pursuant to safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Any statements contained in this call that are not statements of historical fact could be deemed to be forward-looking statements. These are based upon our current estimates and various assumptions and reflect management's intentions, beliefs and expectations about future events, strategies, competition, products, operating plans and performance. These statements involve risks and uncertainties that could cause actual results or events to materially differ from those anticipated or implied by these forward-looking statements. Accordingly, you should not place undue reliance on these statements. For a list and description of the risks and uncertainties associated with our business, please refer to the Risk Factors section of our most recent annual and quarterly reports on Form 10-K and Form 10-Q, respectively, filed with the Securities and Exchange Commission. Also during the call, we will discuss certain financial measures that have not been prepared in accordance with U.S. GAAP with respect to our non-GAAP and cash-based results, including adjusted EBITDA, adjusted operating expenses and adjusted net loss. Unless otherwise noted, all references to financial metrics are presented on a non-GAAP basis. The presentation of this additional information should not be considered in isolation as a substitute for or superior to results prepared in accordance with GAAP. Please refer to the enclosures in our earnings release and 10-Q for a reconciliation of these measures to the most directly comparable GAAP financial measures. This conference call contains time-sensitive information and is accurate only as of the live broadcast today, May 4, 2023. iRhythm disclaims any intention or obligation, except as required by law, to update or revise any financial projections or forward-looking statements, whether because of new information, future events or otherwise. And with that, I'll turn the call over to Quentin Blackford, iRhythm's President and CEO.

Thank you, Stephanie. Good afternoon, and thank you all for joining us. Brice Bobzien, our Chief Financial Officer, and Dan Wilson, our EVP of Corporate Development and Investor Relations, join me on today's call. My prepared remarks today cover progress we've made during the first quarter of 2023 and discuss the growth initiatives for our business. I'll then turn the call over to Brice to provide a detailed review of our financial results and updated guidance. In the first quarter of 2023, we continued to build upon the solid momentum we had exiting last year, recognizing revenue of $111.4 million or 21% growth year-over-year. Our commercial team did a terrific job building upon the discipline and rigor introduced in the back half of last year to capture key strategic wins driven by a continued push into primary care as well as increasing penetration into large and national accounts. The outperformance in the quarter was driven by the strength of our Zio XT business, fueled by better-than-expected volume and another record quarter of new account openings. Additionally, we were pleased with the performance of our return device rate for the quarter as well as the performance of our Zio XT business, which grew 21% year-over-year on a revenue basis, both in line with our expectations. Encouragingly, growth during the first quarter came from across the business as we saw strong contributions from all regions, deeper penetration in our existing accounts and a record number of both new accounts and new prescribers. Volume from cardiologist prescribers grew nicely during the quarter, while contributions from primary care continued to outpace overall company growth. The interest in Zio from primary care physicians continues to grow, evidenced by the significant and growing interest from large national primary care networks. We continue to believe that the primary care channel will be a nice lever for growth as we are in the very early stages of a significant market expansion opportunity. Lastly, we saw continued growth from our large blue-chip accounts as our differentiated commercial strategies to drive further penetration into these valuable partners continue to deliver. Our ability to deliver value across the continuum of care by quickly and accurately detecting arrhythmias for the benefit of patients by enabling better clinical outcomes and, even more importantly in today's environment, improving healthcare resource utilization has resonated with their various stakeholders as we aim to deliver on our mission. Supporting this continued growth is a steady drumbeat of positive clinical data that continues to demonstrate Zio's value proposition and competitive differentiation in the marketplace. The CAMELOT data released at ACC in March was truly game-changing for patients, customers and Zio XT in particular. This was the largest and most contemporary world comparative effectiveness analysis of ambulatory cardiac monitoring, retrospectively analyzing the AC experience of nearly 290,000 diagnostic naive patients. Compared to all other ambulatory cardiac monitors, CAMELOT demonstrated that long-term continuous monitoring with Zio XT was associated with the highest diagnostic yield and the fastest time to clinical diagnosis, the lowest likelihood of retesting and the lowest acute care healthcare resource utilization. With the data now in the hands of our commercial teams and payer relations team, we are excited to further demonstrate how consequential it can be to choose the right monitoring service the first time. As one example of the impact we are starting to see from CAMELOT, the Value-Based Care Council, or VBCC, of the National Association of Managed Care Physicians, or NAMCP, has validated through an independent third-party review of evidence that Zio XT contributes value to health systems and payers. The NAMCP offers educational materials, evidence-based tools and resources to help medical directors from purchasers, plans and provider systems to make effective and informed decisions. The Value-Based Care Council is composed of medical directors and chief medical officers from around the country who have experience and knowledge about value-based care, along with corporate members from the industry who share this interest. In their final report, after an objective review of Zio XT claims and evidence, they showed that the value proposition for Zio XT is credible and objective related to diagnostic yield, analyzable wear time, detection of many types of arrhythmias with lower likelihood of retesting compared with other monitoring types, improved clinical uptimes and decreased time to diagnosis. Additional details and full results of this important collaboration will be announced at a later date. We believe CAMELOT data demonstrates that Zio XT should be the gold standard for long-term continuous monitoring, but we also believe that the commercial release of our Zio monitor represents an improvement to the already high bar we've set for ourselves. In addition to its inconspicuous profile, the viability of the new Zio Monitor allows for comfortable wear and is designed to improve patient compliance and satisfaction. Initial real-world and clinical experience data with Zio Monitor also presented at ACC demonstrated high patient compliance with the potential to extend wear times in the future. Fourteen-day data from 673 patients wearing Zio monitors demonstrated higher compliance and higher quality ECG compared to Zio XT, while 30-day extended wear monitoring yielded additional clinical findings relative to 14 days. Post-clearance evaluations of the Zio Monitor show consistent and even improved performance compared to Zio XT with the potential to greatly improve monitoring and decision-making for more complex patients. We continue to expect the full launch of Zio Monitor later this year with the new platform providing significant product optionality into the future. As we continue to drive towards the realization of opportunities for future growth, we are just as committed to driving growth in a scalable, sustainable manner. As mentioned on our last earnings call, we established a global business services center, and we are working toward ongoing business transformation activities to position the company to maintain patient satisfaction, scale globally and perform more efficiently. We have hired a dedicated GBS leader, along with a team that is now in place and anticipate opening our Manila office during the second quarter. During the first quarter, we also announced internal restructuring to better align the organization to pursue our strategic objectives and to drive operational efficiency, alignment and focus. This allows us to increase the pace of organizational execution by realigning many functions in the business to create synergy, enabling our groups to work more efficiently and to scale more quickly. We look forward to how this will continue to elevate our ability to serve millions more patients as we continue our rapid growth. Furthermore, our commitment to operating as responsible corporate stewards was highlighted in our recently refreshed ESG report released in April. This report and the excellent work by so many around the company that it represents reflects the elevated focus our organization has on ESG matters and reconfirms our commitment to growing responsibly and sustainably for the benefit of patients, customers, communities, employees and the environment. Our company profile and the nature of our products dovetail nicely with ESG initiatives via the reusable, recyclable profile of our Zio device, our continued emphasis on equitable access to care and our unwavering commitment to patients and the communities that we serve. This report is also a nice example of the governance mechanisms we've put in place over the past year to embed ESG policies and initiatives into our operations as we continue to transform the company. We look forward to communicating progress against our road map in the future as a continued driver of long-term value creation for our stakeholders. Before turning to Brice, there is one final item on which I'd like to comment. As we will disclose in our 10-Q filed today, after the quarter closed on April 4, we received an inquiry from the Civil Division of the U.S. Department of Justice seeking information and documents regarding the company's products and services. Our teams are working on responding to the DOJ's inquiry, and we will fully cooperate with the department's request. At this point, we are very early in this process of engaging with them, and it's too early to speculate on the precise motivations behind their inquiry or any anticipated duration of the engagement. As we have more information, we will be sure to provide the necessary updates. In closing, we remain bullish on the business for 2023 and beyond. Continuing on the solid momentum of late 2022, we have begun the new year in a very strong position to drive continued growth in our core business and making the investments necessary to transform the company. We believe that we are well-positioned to capture the opportunities ahead while efficiently scaling our operations and have never been more excited about the future that we see in front of us. With that, I will now turn the call over to Brice to discuss our financial performance.

Thanks, Quentin. As a reminder, unless otherwise noted, the financial metrics that I discuss today will be presented on a non-GAAP basis. Reconciliations to GAAP can be found in today's earnings release and on our IR website. As Quentin mentioned, first quarter results demonstrated continued momentum as we realized revenue of $111.4 million, representing 21% year-over-year growth. This strength was driven by significant volume growth in our core U.S. business, slightly offset by a low single-digit pricing decline in line with expectations. With national CMS rates in place as of January 1, 2023, we began leveraging our San Francisco IDTF with approximately 25% of Zio XT volume processed through the San Francisco location, also consistent with expectations. Looking at new store same-store mix, new store defined as accounts that have been opened for less than 12 months accounted for almost 35% of our year-over-year growth. While we continue to drive record new account openings contributing significant growth, this new store same-store contribution mix is also reflective of tremendous volume growth from existing accounts, implying reduced account turn and increasing penetration in these accounts. Home enrollment for Zio Services was about 20% of volume in the first quarter. Moving down the rest of the P&L, gross margin for the first quarter was 67.9%, representing a 200-basis point decline compared to the fourth quarter of 2022. This decline was primarily driven by expected ASP fluctuation sequentially as we began processing claims for the CMS business at updated national rates beginning January 1 as well as expected slight declines in our commercial realized ASP. However, gross margin in the first quarter of 2023 represented a 100-basis point improvement from the first quarter of 2022. This was driven by a reduction in unit costs to serve as we ramp volumes significantly, and we're able to leverage our fixed-cost infrastructure, offset by year-over-year pricing headwinds. Note that cost of revenue during the first quarter of 2023 included some duplicative costs as we began to leverage third-party providers for certain clinical operations and customer care services to enable growth and scale our operations. First-quarter adjusted operating expenses were $109.5 million, up 13% sequentially and 31% year-over-year. The spend in the first quarter was generally in line with expectations, with the increase primarily driven by increased personnel expenses to support volume growth and elevated commissions for volume outperformance in our core business. There were also some duplicative costs incurred in our operating expenses during the first quarter as we stand up our global business services center in the Philippines. Importantly, we also made incremental investments in R&D as we finalize development of our Zio monitor to prepare for commercial launch later this year, continue developing our Zio MCT product that we plan to submit for regulatory approval in the third quarter and advanced initiatives in adjacent market opportunities. Adjusted net loss for the first quarter was $33.4 million or a loss of $1.10 per share compared to adjusted net loss of $17.9 million or a loss of $0.59 per share in the fourth quarter of 2022. This compares to adjusted net loss of $0.80 per share or a $0.30 decline versus the first quarter of 2022. We reported approximately $5.7 million of expenses related to business transformation activities in the first quarter of 2023, but also recall that in the first quarter of 2022, we incurred $26.9 million in impairment, restructuring and transformation charges primarily associated with the reduction in size of our San Francisco facility. Adjusted EBITDA in the first quarter of 2023 was negative $12 million, reflecting a decline of $13.1 million sequentially and a decline of $7.2 million year-over-year. While this represented a reduction compared to the fourth quarter of 2022 and the first quarter of 2022, this short-term decrease in adjusted EBITDA margin resulted from investments being made to our near-term volume growth drivers as well as long-term initiatives. Turning to guidance, we are updating our outlook to reflect anticipated full-year revenue growth of approximately 17% to 19% compared to 2022, representing a range of approximately $480 million to $490 million, contemplating our outperformance in the first quarter of 2023. Our outlook on anticipated pricing remains unchanged compared to prior expectations. We expect seasonality in line with non-pandemic historic trends with approximately 25% of full-year revenue anticipated in the second quarter of 2023. We continue to believe that gross margin will range between approximately 69% and 70% for the full year. Incremental gross margin improvements will be realized through volume growth contributions to our per-unit cost as well as improvements to our fixed-cost structure. Recall that our full-year guidance contemplates a bit of pressure to gross margin in the middle of 2023 as we ramp to launch our Zio Monitor service into the U.S. commercial marketplace. This will include an evaluation of our current XT inventory levels and may reflect underutilized costs for our Zio Monitor system as we scale the new product. We now anticipate that adjusted operating expenses in 2023 will range between approximately $417 million and $427 million, including updated variable compensation reflected as a result of increased volume demand. This quarter included some seasonal items that will not repeat for the remainder of the year, such as the return of our in-person global sales and leadership meetings for the first time in the last several years. Additionally, as we stand up our global business services center in the Philippines and begin to leverage third parties, duplicative costs incurred in the first quarter will begin to step down over the remainder of the year. As a result, we anticipate that overall operating expense levels on a quarterly basis will step down slightly compared to the first quarter for the remainder of the year. Thus, we continue to believe that adjusted EBITDA margin in 2023 will range between approximately minus 0.5% and 0.5% of revenue. As a reminder, adjusted EBITDA will continue to exclude restructuring costs, transformation costs and stock-based compensation expense. In 2023, we continue to anticipate incurring approximately $15 million to $20 million of one-time non-GAAP business transformation and restructuring costs related to the ongoing globalization efforts to drive efficiency, improve scalability and provide continued high-quality customer and patient experience. We believe that the expenses incurred related to these activities in 2023 will further enable operating leverage into the future, especially as we grow to serve more patients in our core markets and internationally. Note that adjusted operating expense and adjusted EBITDA guidance do not include costs related to the Department of Justice inquiry as we are very early in the process of engaging with the department. Finally, we ended the first quarter in a strong financial position with $176.3 million of cash on hand to drive continued growth in our core business, invest in innovation, and lay the foundation for future expansion. While we continuously review our capital structure to support the best interest of the company and our stakeholders, we are confident in our liquidity position to operate our business for the foreseeable future. We could not be more excited for the strong momentum in the business to continue and look forward to upcoming catalysts that we anticipate can drive growth in 2023 and beyond. With that, Quentin, Dan and I would like to now open the call for questions.

Our first question comes from Allen Gong from JPMorgan.

Congratulations on a strong quarter. I have a quick question about the quarter and a follow-up. It's encouraging to see the quarter starting off well with AT growing 21%. Considering your comments on AT's improvement and better device return rates, how is that performing against expectations so far in the second quarter? What additional indicators would you need to see before potentially raising guidance towards the 20% LRP?

Yes. Thanks for the question. I've been very pleased with what I've seen in the business thus far with return device rates in the AT business. I would say that more or less, we've been right in line with our expectations, if not slightly ahead of where we expected to be, but not materially. You look at the first quarter, the driver of the business is just the underlying volume strength that we're seeing. Our registrations in the quarter were up in the mid- to high 20s as we start to approach 30%, some of the strongest registration growth we've seen in almost two years now, and that's getting back into some COVID comparisons that start to get a little bit unique, right? So the registration growth has been phenomenal. And that's really what's driving the overall growth in the business. I still continue to believe that as we make progress with return device rates and AT returns to historic growth rates, that has the opportunity to provide some upside to the guidance that we've laid out today. But really, the strength of the quarter was driven by the registration growth in the business.

Got it. As for the Department of Justice inquiry, this is new information for us. I understand it's civil, so we hope any potential downside is limited. Do you have any insight into what they're examining, the expected timelines, any updates on the process, and the possible impact of the inquiry?

Yes. I think it's a bit early at this point to really articulate anything clearer around the matter itself. We certainly will engage with the DOJ and try to learn as much as we can, and we'll communicate as we have more clarity around what that looks like. I think at the end of the day, we know that within this industry, these things occur from time to time, we understand that. I will tell you, we've done an incredible amount of work over the course of the last 12 months to 18 months with the new leadership team in place, building out incrementally more robust capabilities we've put in place a chief risk function, a chief risk officer. We have a dedicated compliance function. I mean we've continued to mature the organization over the last year or so that continues to give me confidence that quality, compliance, all of these things are very important to us and will continue to be, and we're elevating our capabilities in the organization. But to give you any specifics on what they might be focused on or where their focus is at, it's just too early at this point, and there's not a whole lot more we can comment on at this point in time. But as we do get more information, we'll certainly be sharing it.

Our next question comes from Margaret Kaczor from William Blair.

Congratulations on the quarter. It seems that the momentum for PCP has continued. From our channel checks, we've noted improved access to iRhythm compared to before. Are there particular partnerships where this is more evident? Additionally, are you noticing a different type of patient demographic now compared to before establishing these partnerships?

Thank you for the question. On the access side, we dedicated significant time in 2022 to ensure that patients who needed our product could access it. Almost 93% of patients from a commercial perspective have access to our product, most of whom do not require prior authorization for Zio XT. We've made great strides in increasing access and raising awareness. In the marketplace, we've observed that many cardiologists are advising primary care physicians, especially within their networks, to prescribe and apply our product earlier in the patient care process. This approach helps them pinpoint which patients require further attention. Cardiologists are advocating for the use of this device in primary care settings. We are actively targeting the primary care network; for instance, we announced a partnership last quarter with One Medical and are expanding with additional primary care networks. This will enhance product utilization in primary care and elevate awareness of its value. Overall, it's a combination of improving access and significantly raising awareness in the primary care channel regarding the user-friendliness of our product and how it aids in patient management.

That's great. And then just one real quick on the Zio Monitor in terms of what's being assumed in the mix between Monitor and Zio XT once it does enter the full launch?

Yes. It's a good question. Thanks for asking. I would say from a guidance perspective, we're not necessarily anticipating an acceleration in volume or anything specifically related to Zio Monitor. What I would say is we absolutely believe this is a great product, and there's absolute opportunity for upside with it. But from a guidance perspective, not necessarily anything baked in specific to Monitor.

Our next question comes from Marie Thibault from BTIG.

Congrats on a great quarter. I wanted to ask my first here on the Novitas final LCD that was out. We certainly got some questions on it. And I just wanted to hear your latest thoughts on the risk around that LCD, the possibility of spread to a Noridian or a different geography. And any details you can offer on the number of prescriptions that would meet the EKG requirement. Any details around that?

Marie, thanks for the question. Look, I don't view the final LCD out of Novitas as anything that gives me any concern really at all. I don't think it's significantly restrictive. I think it mirrors quite frankly, many of the commercial policies that are already out there that we navigate in and around every single day. I mean at the end of the day, if you look at where they landed with the final position of their LCD. The reality is there are a handful. You can probably count 10 to 12 different criteria that so long as the patient is meeting or the physician believes it is taking place enable or allows them to prescribe a pass technology. I think the initial concern was, is there going to be a requirement for a 12-lead ECG to be performed before they can step into something else? That's not the case at all. That's one of the 12 criteria, but they're all ours if you will, meaning if you meet any one of those significant list of criteria. So I don't view this as anything that's going to impact the momentum in the marketplace. Again, it's very much in line with what we see with the majority of our commercial payers. If you get into the details even on the 12-lead ECG, for example, you just start to do some market checks. You're going to find that north of 80%, upwards of even 90% of physicians are already capturing this information, and we're providing it, like I said, in the commercial payer universe already. So I don't have any concerns around it. Certainly, we're mindful of it, but it's a normal part of how we operate the business today and how the physicians, I believe, interact with their patients today. So no real concerns from our perspective there.

Okay. Good to hear you confirm that. I'll ask my follow-up here on the San Francisco facility. It sounds like about 25% of the volumes being processed through that facility. What are you expecting in the numbers you've given us for Q2 on guidance in terms of the shift toward that? How is hiring and all the hurdles you need to jump to shift more volume going on that side?

Sure. Marie, it's Brice. So yes, we still anticipate about 50% of the full-year volume running through the San Francisco IPF. No differential from what we anticipated from the beginning of the year. As it stands now, hiring is going well. It's still something we monitor on a regular basis, but no deviation from the contemplation in the original guidance.

Our next question comes from Nathan Treybeck from Wells Fargo.

Can you talk about the ASP declines you saw as you began processing at the new national rate? And how should we think about this as you shift your volumes to the San Francisco IDTF?

Sure. Jason, this is Brice. So in the first quarter, if you remember, looking back into 2022. From a CMS perspective, we're still navigating most of the volumes through the Houston IDTF. At that point, it was at a lower ASP point than what we ultimately ended up pushing through Chicago. So specific to XT, I would say there's actually a bit of pricing tailwind from a CMS perspective on the XP side. Now I will say on the AC side, it's almost exactly the other way and they effectively net each other off. There's a bit of overall pricing pressure. But on the AP side, the national rate was established and, call it, 11% less than what we saw in 2022. All volumes on the AC side go through San Francisco, both in 2022 as well as 2023. So that 11% impact is basically the way you can think about AC. On the commercial side, that low single digits played through. A portion of that was those commercial contracts that are tied to the CMS rate. The other portion of that would just be normal course of business and contracting. So effectively, it came in right in line with expectations as we think about Q1. Again, that's the reason we reiterated the ASP guide for 2023.

Great. Regarding the Zio monitor, what is the expected timeline for transitioning all your XT volumes to the monitor? Additionally, how should we anticipate the impact on margins as this transition occurs?

Yes. I think from a commercial perspective, you're going to see that migration taking place over the course of 2024. Obviously, I think as quickly as we can move towards the monitor, we're going to want to do that. But at the same time, we're ramping production volumes. We're introducing some automation on the Zio Monitor so that we can produce that in the lower cost and time and at scale. All of those are going to play into how quickly we can work through that conversion. But the hope is to get to monitor as quickly as we possibly can. I think in terms of the gross margin progression, Brice, certainly feel free to speak to that. But we know that we're going to have a bit of pressure in the third quarter, late third quarter as we think about transitioning into delivery lease of monitor, and it's not at full scale. So it's going to put a bit of pressure on the gross margin. We also got to think about how we step out of the DLX product. And do we have any inventory charges that we have to look at from a reserve excess obsolescence? And so we'll pay attention to those sort of things. All of which is contemplated in our forward-looking guidance. Once we get into monitoring start to really fill that and ramp it and work into the efficiencies of that automation, I think you're going to see some benefits in that gross margin line. So we'll give more color and clarity around that when we're ready to set expectations for '24, but we certainly see Zio Monitor as something that can drive some nice gross margin improvement for us into the future.

Our next question comes from Cecilia Furlong from Morgan Stanley.

I wanted to ask about AT just following some of the recent disruption. It did look like strength in the quarter. But as you think going forward, are you back to what feels like a normalized growth rate for AT? How are you factoring that into your guidance relative growth versus XT? And then I wanted to ask to just tie in with that for MCT coming out in the future. How you're thinking about the time frame for that? If it's 30 days shorter? Just love your outlook at this point.

Sure. So I think from an AT perspective, Brice mentioned this in some of his comments earlier in response to one of the questions. We saw, I would say, low teens in terms of pricing pressure coming out of the AT business. Yet the CMS rate that was down about 11% concerning AT. On the commercial side, a couple of points of incremental pressure there. So think about it as the low teens in terms of pricing pressure, and we communicated that the AT business grew around 21%. So from a volume perspective, AT was up in the mid-30s. That's down from where it was at last year, which was closer to the upper 40s. So we're not back to those historic growth rates, but yet it is growing in line with how we expected it would in the guidance that we set. To the degree that we can get that back up into those historic growth rates, then there's upside to the financial forecast that we put out there, but that's not something that we necessarily want to get ahead of ourselves with. We want to see that show up in the results and then we can reflect it more aggressively in the financial guidance that we put out there. But I will say we've been pleased with the progress. With respect to Zio MCT, we hope to get on file with the FDA here in the mid-part of the year. Everything is tracking very well to that. Really pleased with the progress the teams have made to get on file from an FDA perspective. Then we would look to have approval sometime out in '24 and then potentially have that product into the market in the back part of '24. The idea would be certainly to have an extended wear period beyond the 14 days that our Zio AT has today. Not sure we get all the way to the 30 days, but we're going to be a whole lot closer to it. I think start to really eliminate this argument from a competitive perspective that 14 days may not be enough for what they're looking for. While we don't get all the way to 30 days, it's close enough that it starts to eliminate that issue for us altogether. I'm excited about what we're going to see with Zio MCT. I think it's a terrific product. I would say we're not waiting for MCT to continue to work on closing the gaps in our AT portfolio. We'll introduce the AF burden onto our Zio product here in the next 30 to 45 days or so into the U.S. marketplace, which continues to enhance the value proposition of that particular product for us. So there are reasons we can get back to those historic growth rates this year. But we want to see that play out before we start to really reflect it in our guidance more aggressively.

Great. I appreciate the color. And then just turning again to PCPs and the strength that you've seen there. I don't know if there are any metrics you can put around it, but just how you're looking at '23 contributions going through that channel versus what we saw in '22? And from a top-line standpoint, really how you're thinking about that reflected in your overall guidance range.

Yes. I will tell you, I think a lot of the volume strength that we saw in the first quarter, again, a record for us in nearly two years now is being fueled by the strength of the primary care adoption of the technology. Now it's interesting in terms of how it's showing up. I think you see a little bit of this in the statistic that Brice pointed out in terms of 35% of our growth is coming from new accounts and, call it, 65% coming from existing accounts. But what you're seeing is in those existing accounts, a lot of further penetration into the account itself and starting to work with the primary care physician within the account versus just the cardiologist. It's driving a lot of the growth in our existing accounts as well as we move into other channels of the account we're already in. I think it's a bit too early to give specific measures around the progress with respect to PCP. I think that's something we'll continue to think about into the future. But right now, I would tell you the majority of the outperformance is really coming from these incremental channels that we're starting to really position the product forward, but also utilizing the voice of the cardiologist just in terms of how easy the product is to further upstream and get into these other channels. It's quite encouraging in what we're seeing. As I shared, the strength of the quarter was on the back of the true underlying volume in the period itself. We want to see that continue to play out before we update any financial guidance but very encouraged by what we're seeing there.

Our next question comes from Richard Newitter from Truist.

Quentin, I was hoping or wondering, could you comment a little bit on the month-to-month trends through the quarter, particularly as you exited in March and what you saw in April.

It's a good question, Rich. I will tell you in the first quarter, January, February were incredibly strong months for us. We did see March pull back a bit. And we saw that remain at that lower level through the early part of April, but it came back very strong in the back part of April and has been very strong here in the very early part of May as well. I attribute that; this is something we pay very close attention to, and I think have a good finger on the pulse. I do think the holiday period, the spring break period through that late March, early April time frame, did feel like it was a bit heavier than what we've seen historically. Through some other channel checks, that's been validated. But what we've seen in late April and into the early part of May has been really, really encouraging; and something that we're very excited to be seeing. I think it comes back to why we just don't want to get ahead of ourselves at this point in time, but the most recent trends in the business are something we're very pleased with.

Okay. That's really helpful color. And then maybe just a follow-up here. Thinking about the guidance move from 16% to 18% to 17% to 19% now year-over-year. You just did 21%. I guess A, any color you can give on the quarterly cadence between 2Q and 4Q? Anything you'd want to call out here? Do you feel comfortable more or less where consensus is for 2Q? And then B, why wouldn't you hit the 20% marker or stay in the 20% arena for longer? What's the reason why growth would decelerate?

Yes, Rich, I think it's a fair question. I think there's certainly the potential there to be at 20%, but I look at it as we're a quarter into the year. We certainly aren't going to get out ahead of ourselves. We're incredibly bullish on what we're seeing in the business. But I think there's a lot of economic uncertainty that continues to remain out there, and we want to be mindful of that. When we put something out there and tell you that we're going to deliver on it, we want to deliver on it. I think we just need a little bit more time to get comfortable to raise it up into that 20% range. But certainly, if you look at the first quarter, return device rates, we're not all the way back to where they were in the prior year. '18 is not all the way back to where it was yet volume was incredibly strong, and we grew north of 20%, nearly 21%. So we know that we can grow more than 20%, but we want to see this continue to play out for a little bit of time before we get ahead of ourselves. In terms of the quarterly cadence, I look at Q2; I'll give you a bit of color around it. Historically, we're going to drop 24.5% to 25% of revenue into the second quarter. I think that's the right way to continue to think about it sequentially; it's probably going to step up right around that 8% range or so. It's how we've modeled it. I think that's the way you ought to think about it for the time being. If you're around those ranges, I think we're all probably thinking about the second quarter in a similar way. We'll see how volumes play out and we'll deal with the back half of the year as we have more confidence in what the volumes might look like. Right now, we feel very good with that back-end guidance that we put out there.

Our next question comes from Bill Plovanic from Canaccord.

I'm a bit different in my approach. I'm interested in how Medicaid varies from state to state, especially since before the CAT 1 code, many states weren't pursued for payments. Can you share what changes you've observed since the CAT 1 code was implemented? Additionally, how should we evaluate the potential opportunity for capturing this going forward?

Bill, it's Brice. Good question. Medicaid is one that we're actually really coming onto our radar, and frankly, we've internally set up a committee that's focused on just this. So we're really taking a state-by-state approach in certain situations where we see the highest portion of our patient population ultimately coming through those channels. What you have to do; you have to have a code in place, not only with the CAT code for broader coverage from basically the category being in place on the Medicare side but also have that code in place with the individual states from a Medicaid perspective. Honestly, we're going down the line and saying which ones do we work on first. Some are a little bit easier to get after than others, but we have a process where we're working into each. Now I will tell you, for the most part, we're still covering those patient populations. What’s happening is effectively it's going without payment. What you'll see as we make progress is that non-contracted bucket that we reported in our 10-Q will continue to shrink. Ultimately, it will shift up, and you'll start to see the ASP benefits associated with it. I think for us, I would say it's absolutely something we think about, and we're making it a priority, and we're pushing it forward.

Okay. And then if I could just ask on international. Just any update on Japan designation reimbursement?

Yes. Thanks, Bill. Certainly excited by Japan. I think we're going to hear very shortly the high medical needs designation, whether we're going to receive that or not; I expect it sometime within the next 30 days. Once we have that, our file is ready to be submitted from a regulatory perspective, and we'll be on file immediately. I think we'll file any time here in the next, call it, 30, 60 days there in Japan and hope to have an approval sometime in the course of '24 and then moving on to getting the product in the market. But we're very close. I think that it's probably quite honestly been a month or two beyond where we were hoping to be but a high medical need is something that's worth pursuing, and we're going to get an answer to it soon.

Our final question comes from Suraj Kalia from Oppenheimer.

Quentin, can you hear me all right?

We got you.

Sorry, I'm on a train. So pardon the background noise. Quentin, I'll ask two questions, both of them together. The Zio Monitor and its introduction for, let's say, the Zio XT 300 day, should we think about a staged approach first 21 days and then 30 days? And what's the status of the gateway for 21-day battery? And my second question, Quentin, where are you on the discussions with the payers for off-shoring the report readout and analysis, you'll set up a facility in Manila. Curious how payers are responding to that.

I appreciate the question. Look, Zio Monitor, just to be clear, the initial launch of Zio Monitor will replace Zio XT, which is a 14-day product. The initial monitor will be put into the market as a 14-day product. That platform, the very same form factor, is what will be used for our Zio MCT product when we launch that, and that's going to be anywhere from 21 to 30 days in terms of this wear period. We continue to work through that with respect to Zio MCT, but that will be the longer duration wear period. Now I think what you're referring to is we had put out a study; there was some trial data published back at MCT that just demonstrated the Zio Monitor, which again is the same form factor as what Zio MCT has, very successful wear properties with it all the way out to 30 days. We will keep Zio Monitor in terms of what's going to replace Zio XT at the 14-day period for the time being, but I think it creates some flexibility if we want to think about that over a longer duration. With respect to the gateway, the gateway is something that we're working with also to extend the duration of its usability, if you will. Today, well, it's 14 days with Zio AT, but with Zio MCT, I think we can get that out to 21-plus days. I think if we start to look at that in a little bit of a different way, maybe where we make it rechargeable, then of course, it can go as long as it needs to go, depending on how many days we have the Zio MCT-pats working, which could be up to 30 days potentially. It gives us a lot of flexibility from that perspective. On the payer side regarding some of the off-shoring or setting up the Manila facility, I would tell you we're making very good progress. I would say some of the largest payers we've already worked through and have the consent to be able to process their claims offshore. Of course, anything with the U.S. government, we're keeping all onshore and we're very careful about that from a compliance perspective and have the proper controls in place to ensure that we're monitoring that really on a case-by-case basis. I've been pleased with the progress with the payers, and we started with the largest payers and now we'll continue to work down the list to some smaller payers. I think to be completely transparent with you, there are some payers who prefer not to leverage the offshore capabilities. We respect that, and we can certainly accommodate that in our workflow and make sure that's the case. But the big payers are pretty well understanding of it. In many cases, many of these big payers have off-shoring capabilities of their very own set up in the same city centers that we're looking at setting up operations with, so we feel good about that, and we've made a lot of good progress around that effort.

Thank you. We have no further questions. So I will now hand back over to the management team for closing remarks.

Terrific. Well, thank you. I will say we're extremely encouraged by the start of the year and the momentum that we see building within our business as we focus on driving towards our strategic objectives. I want to take the opportunity to thank all of our teams for their hard work, their dedication to really advancing our card as we aim to serve all patients who can benefit from our products and services, and that list continues to grow each and every day. Thanks for joining our call, and we look forward to catching up in the next half.

This concludes today's call. Thank you for joining. You may now disconnect your lines.